Prognostic factors for cure following treatment of onychomycosis.

OBJECTIVE To examine if host baseline factors and week 24 mycology results are associated with mycological and clinical cure in patients with onychomycosis treated with oral terbinafine. DESIGN Open pilot study to determine prognostic factors in the treatment of onychomycosis. SETTING Outpatient dermatology clinic. PATIENTS A total of 199 patients from the Icelandic arm of a trial comparing continuous terbinafine with intermittent terbinafine in onychomycosis were recruited for additional observation. MAIN OUTCOME MEASURES Mycological, clinical and complete cure of the target toenail 72 weeks after treatment was initiated. RESULTS Patients with matrix involvement or slow nail growth were less likely to reach mycological, clinical and complete cure. Lateral involvement affected complete and mycological cure rates negatively. Patients with a dermatophytoma were less likely to reach mycological cure. Patients with a history of prior infection, men and older patients were less likely to reach clinical cure. Positive culture at 24 weeks affected mycological and clinical cure at 72 weeks negatively. LIMITATIONS Only patients treated with terbinafine were considered. CONCLUSIONS Several host-related factors at baseline and positive culture at 24 weeks had negative effects on cure of onychomycosis 72 weeks after treatment was initiated. This finding merits a large study on prognostic outcome factors in onychomycosis.